An electric heat gun fell onto a bed on Friday afternoon, igniting a fire in a house in Springs where construction was underway, an East Hampton Town fire marshal said this week. A painter was working at 36 Cedar Ridge Drive, patching drywall in a bedroom where a ceiling fan had recently been installed, when he began using the heat gun to speed up the drying time of Spackle, according to Tom Baker, the fire marshal. The fire broke out at about 2:20 p.m. “He propped [the heat gun] up on top of a fiberglass step ladder,” Mr. Baker said, and left it on while he went out to get more paint from his truck. “Upon his return, he heard the smoke alarms sounding. He saw smoke, closed the door, and called 911.” The Springs Fire Department put out the blaze quickly, said Darrin Downs, first assistant fire chief, calling it “a great stop.” The flames were confined to the bedroom, which was destroyed. There was smoke and water damage in the rest of the house, Mr. Downs and Mr. Baker said.The fire marshal said the heat gun had ignited a dropcloth and the bed itself. “I found the heat gun in the debris and determined it to be in the “on” position,” he said. The painter’s name was not released. He did not have a license to work in the Town of East Hampton. It was not immediately clear whether charges would be filed.